What is the mass of an $fcc$ unit cell if the mass of one atom of an element is $6 \times 10^{-23} \ g$?

• A
  $24 \times 10^{-22} \ g$
• B
  $4 \times 10^{-23} \ g$
• C
  $2.4 \times 10^{-22} \ g$
• D
  $2.4 \times 10^{-23} \ g$